I just today transfered my white collar work based ARC to a JFRW based on household registration. I didn’t need to show either a background check or a medical exam to do so, even though it says both are needed on the website. My guess is that if you’re going from a visitors visa to a JFRW then you’ll need those two documents since you’re completely new to their system. Anyone who’s currently working here already and planning on obtaining a JFRW need not worry about dealing with the hassle and wait of getting the background check. Keep in mind though, that I did get married here and do have household registration. It might be different under other circumstances.
If I should update this info at all, or add it to an already existing thread let me know and I’ll do so. I want this info to be easily found when searched for in the future.